In the present study, an axis-symmetric electro-thermo-mechanical model has been developed to analyze a deformation process by continuous resistance heating. To obtain the transient temperature field prior to forming, a novel temperature-dependent model of the contact resistance was developed in the thermal-electrical analysis. The influences of the contact resistance, the current intensity and the die geometry on the temperature distribution were investigated. In the subsequent electro-thermo-mechanical analysis of the forming process by continuous resistance heating, the variations of the billet temperature distribution, forming force were obtained. The simulation results correspond well with experimental measured values. Furthermore, the influence of a current increasing during forming on the billet temperature and forming force was predicted in order to optimize the forming technology by continuous resistance heating.